Jantar Mantar is an astronomical observatory located in Jaipur, Rajasthan, India. It was built in the early 18th century by Maharaja Sawai Jai Singh II, who was a passionate astronomer and mathematician. The observatory is one of five similar structures built by Jai Singh in various parts of India.
Jantar Mantar is a complex of 19 instruments designed to measure various astronomical phenomena such as the position of stars, the altitude and azimuth of celestial bodies, and the time of day. The instruments are made of stone and brass and are arranged in an open-air space that covers over 18,000 square meters. One of the most impressive instruments at Jantar Mantar is the Samrat Yantra, which is a massive sundial that can measure time accurate to within two seconds. The instrument stands 27 meters tall and has a shadow-casting arm that is 22 meters long.
Jantar Mantar is considered a masterpiece of Indian scientific and architectural achievement and is recognized as a UNESCO World Heritage Site. It is a popular tourist attraction in Jaipur and attracts visitors from all over the world who come to marvel at the intricate astronomical instruments and learn about the history of Indian astronomy.

Jantar Mantar, Jaipur
Do you want to know more about Jantar Mantar? Here are 31 interesting facts about Jantar Mantar.
- Jantar Mantar is the largest and best-preserved of the five astronomical observatories built by Maharaja Sawai Jai Singh II.
- The observatory was built in 1734 and took over seven years to complete.
- Jantar Mantar was designed to measure time, predict eclipses, and track the movements of celestial bodies.
- The instruments at Jantar Mantar were made using stone and marble, and some are over 300 years old.
- The observatory covers an area of 18,700 square meters and contains 19 different instruments.
- The name Jantar Mantar is derived from the Sanskrit words “yantra” (instrument) and “mantra” (formula).
- Jantar Mantar is one of the most significant historical landmarks in Jaipur, Rajasthan.
- The observatory is a UNESCO World Heritage Site and is recognized as an important cultural site in India.
- The Samrat Yantra, the largest instrument at Jantar Mantar, is a massive sundial that stands 27 meters tall and can measure time accurate to within two seconds.
- The sundial’s shadow-casting arm is 22 meters long and moves at a speed of 1 mm per second.
- The Samrat Yantra is also used to measure the declination of the sun and track the movement of stars.
- The Jayaprakash Yantra is a hemispherical instrument used to determine the position of celestial objects.
- The Mishra Yantra is a combination of five different instruments used to measure the altitude and azimuth of celestial bodies.
- The Ram Yantra is a massive instrument used to measure the altitude of stars and planets.
- The Jai Prakash Yantra is used to measure the position of celestial objects and is similar to the Jayaprakash Yantra.
- The Laghu Samrat Yantra is a smaller version of the Samrat Yantra used to measure time.
- The Rashivalaya Yantra is used to measure the position of the sun in relation to the zodiac.
- The Dakshin Bhitti Yantra is used to measure the altitude and azimuth of celestial objects.
- The Unnathamsa Yantra is used to measure the altitude and azimuth of celestial objects.
- The Kranti Vritta Yantra is used to measure the latitude and longitude of celestial bodies.
- The Yantra Raj is a combination of five different instruments used to measure the position of celestial objects.
- The Kapala Yantra is a hemispherical instrument used to measure the altitude of celestial bodies.
- The Shastansh Yantra is a combination of six different instruments used to measure the altitude and azimuth of celestial objects.
- The Disha Yantra is a set of two instruments used to determine the direction of celestial objects.
- The Nadivalaya Yantra is a circular instrument used to measure the altitude and azimuth of celestial objects.
- Jantar Mantar has been used to predict eclipses and other astronomical events for over 200 years.
- The instruments at Jantar Mantar were designed to be easy to use and could be operated by a single person.
- The observatory was used as a training center for the study of astronomy and mathematics in the 18th century.
- Jantar Mantar is considered a masterpiece of Indian scientific and architectural achievement.
- The observatory has been featured in several films and television shows, including “The Darjeeling Limited” and “The Amazing Race.”
- Jantar Mantar is a popular tourist attraction in Jaipur and attracts visitors from all over the world who come to marvel at the intricate astronomical instruments and learn about the history of Indian astronomy.
Jantar Mantar in Jaipur is an architectural marvel and a testament to India’s rich scientific heritage. The observatory’s 19 instruments were designed with precision and mathematical genius to accurately measure astronomical phenomena such as the position of celestial objects and the time of day. For over 200 years, Jantar Mantar has been used to predict eclipses and other astronomical events. The observatory is not only a cultural and historical landmark but also a popular tourist attraction that fascinates visitors from all over the world. Jantar Mantar stands as a testament to the intellectual achievements of ancient India and remains an important site of scientific study and astronomical observation to this day.